Issue with User-Defined Function - Heat Source depending on Coordinates

[ftrillaudp]

Dear all,

I am trying to define a local heat dissipation through a Heat Source which depends on space location and time. Thus far, I am working only on the spatial distribution of the heat source in a racetrack coil.
The heat is dissipated in a sphere of radius R so that R is larger than the distance between nodes. I compute the distance between the center of the sphere and any points in the mesh of the racetrack. Assuming Pd(x_d,y_d,z_d), the center of the sphere, the distance d to any points P(x,y,z) is given by: d = SQRT((x-x_d)^2+(y-y_d)^2+(z-z_d)^2). I impose a condition on d and R, If (d > R) then there is no dissipation Q = 0 else Q is equal to a given value Qd.

I have implemented the scheme in an UDF. However, it does not seem to work properly and I am wondering if I am using the proper coordinate system points (x, y, z). I have attached the UDF and the case.sif file as well as a result to show the issue. The heat source is not located at the expected position in the racetrack coil.

I have tried to change the size of the mesh but the issue persists. I am stuck at this point.

The UDF with additional comments is also given below:

FUNCTION getDisturbance(Model, n, tt) RESULT(Q)
! Elmer module
USE DefUtils

IMPLICIT NONE
TYPE(Model_t) :: model
INTEGER :: n
REAL(KIND=dp) :: tt
REAL(KIND=dp) :: X, Y, Z, t_ini, Dt, Qd, Q
REAL(KIND=dp) :: R, x_d, y_d, z_d, d

t_ini = 0.003
Dt = 0.01
Qd = 7000.0

! get local coordinates of the nodes
X = model % Nodes % x(n)
Y = model % Nodes % y(n)
Z = model % Nodes % z(n)

! Half side length of the cubic disturbance
R = 0.007 ! distance between node of the order of 0.005 m
! Center of the disturbance:
x_d = 0.0
y_d = -0.026 ! somewhere in the middle of the straight section of the racetrack
z_d = 0.0
! distance to center of disturbance
d = SQRT((X-x_d)**2+(Y-y_d)**2+(Z-y_d)**2)

PRINT 1,(R-d)
1 FORMAT(' R-d: ', EN12.3)

IF (d > R) THEN
Q = 0.0D00
ELSE
Q = Qd
PRINT *, "ON POINT"
END IF

END FUNCTION getDisturbance


Best,

Frederic

[kevinarden]

Would need the mesh to check.

[ftrillaudp]

Here is the mesh at:

https://drive.google.com/file/d/1PtfS7f ... sp=sharing

I am adding the material properties as well. These are tables in a subfolder:

https://drive.google.com/file/d/1getvP9 ... sp=sharing


Best,

Frederic

[ftrillaudp]

I have found my mistake. It was a simple typo in the computation of the distance d, instead of the correct d = SQRT((X-x_d)**2+(Y-y_d)**2+(Z-z_d)**2), the code read d = SQRT((X-x_d)**2+(Y-y_d)**2+(Z-y_d)**2) a typo in the last square!

It works now.

Thanks for replying, best,

Frederic